Two-matertal, P and A plug

ABSTRACT

A plug for Plug and Abandonment (P&amp;A) operations. The plug is a two-part plug of bismuth-based alloy and resin, allowing for sealing of an oil well using two different mechanisms with a shorter plug. The sealing can be rock-to-rock and/or cast-in-place.

PRIOR RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 16/386,198 filed on Apr. 16, 2019, which is a continuation ofU.S. patent application Ser. No. 15/948,322 filed Apr. 9, 2018, now U.S.Pat. No. 10,316,612 which issued on Jun. 11, 2019, which claims priorityto U.S. Provisional Application No. 62/484,624 filed Apr. 12, 2017, allof which are incorporated by reference herein in their entirety for allpurposes.

FIELD OF THE DISCLOSURE

The disclosure relates to plug and abandonment operations, andspecifically to a two-material plug that has multiple sealing mechanismsand improved structural integrity over the use of either material alone.

BACKGROUND OF THE DISCLOSURE

There are several thousand active oil and gas wells located around theworld, with thousands more to come on-stream in the next ten years. Thewells differ in design, size, cost and economic benefit, but have onething in common—sooner or later they will be decommissioned andabandoned.

The decision to plug and abandon (P&A) a well or field is invariablybased on economics. Once production delivers less than the operatingexpenses, it is time to consider abandonment. In some situations, thedecision is made with the knowledge that considerable reserves remain,but the cost to extract these resources is more than the projectedincome.

There are regulatory requirements associated with the P&A process toensure that strata, particularly freshwater aquifers, are adequatelyisolated. The plug's length, cross-section, position and verificationtests are typically regulated and depend on the type and location of thewell being plugged. Thus, the cost to P&A a well can vary by manymillions of dollars depending on location, and whether the well isoffshore or onshore. Minimizing costs, without sacrificing wellintegrity, is critical to operators, who make a significant investmentwith no financial return in the case of P&A operations.

FIG. 1 displays a simple schematic of a basic plug. A modern requirementfor a permanent well barrier is that it must include all annuli,extending to the full cross section of the well and seal both verticallyand horizontally. In FIG. 1, a cement plug (104) is sealing verticallyinside the casing and sealing both horizontally and vertically in thecasing-formation annulus (102) above the casing shoe (103). However,cement is easily contaminated with mud, which results in placementissues and often results in plug failure.

Because cement is susceptible to failure if contaminated by drilling orother fluids, yet long length cement plugs are required, other materialshave been investigated for use as plugging material. Resins seal byadhesion, and have resistance to many caustic and corrosive chemicals,excellent mechanical properties, such as high strength and high shear,and flexibility and toughness after setting. However, resin plugs can bemore difficult to set successfully because of the relatively complexchemistry and the need for time to cure. Further, resin plugs will falldown the well bore and annulus unless the bore and annulus are plugged.They must be set on a base and the annulus sealed. Shrinkage of theresin can also occur as it cures unless formulated correctly and canlead to micro-annuli and cracks in the sealant and/or lack of bonding ofthe seal, plug or connection to its surroundings.

Although cement and resin are the most common plug materials,improvements in plug composition and methods are desired to reducecosts. One alternative is to “cast-in-place” a metal plug. A eutecticalloy, such as an expandable bismuth alloy, is heated in place to form amolten liquid metal that easily penetrates small crevices and cracks,and hardens in place forming a tight plug. The specific gravity of themetal being much higher than any fluid, results in effective placement.A heater tool, described in WO2011151271 and WO2014096858, iscommercially available from BiSN Oil Tools, and can heat such cast-inplace bismuth alloy plugs. The BiSN Wel-lok M2M Bridge Plug™ can run onstandard wireline, slick line or coil tubing. It uses a bismuth-basedalloy that is melted in situ by a chemical reaction heater that usesmaterials, such as thermite, to generate heat. However, this tool canonly heat a limited volume of alloy at a time, and thus other methodsand tools are still needed for P&A.

Thus, there still exists a need to improve plug formation in P&Aoperations while also decreasing cost and time. Ideally, the new plugswould be safe, create a reliable barrier, be cost effective, and bothfaster and easier to perform than current methods.

SUMMARY OF THE DISCLOSURE

Described herein is a new plug and method for plug and abandonmentoperations. Specifically, the new plug combines resin and a eutecticalloy to provide two redundant sealing mechanisms. This results in ashorter plug being needed for an improved sealing. Methods of installingthe plug are also described.

Plugging and abandonment (P&A) regulations vary among states and betweencountries, but all regulations prescribe the depth intervals that mustbe plugged, as well as the materials that are allowed in pluggingpractices. For instance, in the North Sea, current P&A guidelinesrequire plugs between 30 to 50 meters in length. To set such plugs, thewellbores undergo section milling, or perforation, wash and cement (PWC)processes. Both operations require substantial amounts of time andexorbitant cost. Further, milling or perforating 30-50 meters is notalways economical or feasible, especially where the area to be pluggedhas multiple strings of casing that need to be removed.

Shorter plugs would require less casing being removed and reduce costs.One proposal for reducing the size of plugs is to utilize more than onematerial for the plug. For example, one option that has been presentedis the use of two-material plugs using cement and resin. Generally,these plugs consist of a base plug, annulus seal, a resin layer, andthen a cement layer. However, the resin requires time to set before thecement can be placed, thus delaying the plugging operation. Further, thecement is used just to hold the resin in place and is not a rock-to-rockplug of the formation. The problem with this plug is the time to set,including the based plug and annulus seal. If the annulus or base is notsealed correctly, all the resin could fall down the well bore or annulusas the resin will have a higher specific gravity than the fluid in thewell.

In response to the long-felt need for better plugs that are smaller andmore economical to place, Applicant has developed a two-material plugthat overcomes the problems associated with the resin/cement plug.Specifically, the currently described plug utilizes eutectic alloy-basedmaterial and resin to form the seals. The eutectic alloy material,preferably bismuth-based, is added to the wellbore first, where itundergoes a heating step to melt the alloy, allowing it to expand andform a “cast-in-place” metal seal. This alloy plug acts as a base forthe resin while sealing the annulus and wellbore with a rock-to-rockplug. This metal seal, along with the sleeve or frame of the heater usedto melt the alloy, provides a structural component for the resin toattach thereto. The resin is the second layer to be added and it tooforms a rock-to-rock seal that is cast-in-place across the wellbore aswell as sealing the heater frame.

The order of the materials used in the plug is important. Thebismuth-based alloy is immiscible with fluids in the wellbore and iscorrosive resistant. Thus, no long-term failure due to fluid contact isexpected. By placing the resin above the metal seal, the resin, whichcan also be immiscible in the fluids, is protected from hydrocarboncontact that can negatively affect the resin. As such, the alloy formsthe base and seals the annuli. Further, the flexural failure of theresin section is reduced through the use of the metal plug, and theheater sleeve and its components, as reinforcement. This is analogous tosteel reinforcement in concrete.

The described plug has a wide potential use in plugging operations, andcan be used in all offshore producing areas. Further, smaller openingsare needed for accessing the annular space. The described plug isexpected to decrease abandonment costs by 25% or more for wells thathave two strings of casing across the area to be plugged.

This new plug has many advantages over currently used plugs and otherproposed two-material plugs. First, the two materials use differentsealing mechanisms. The eutectic alloy seals by expansion and the resinseals by adhering to a surface. This reduces the probability of plugfailure because either of the materials can plug the wellbore on its ownand has different properties and thus differential failure rates underthe same conditions. Further, the eutectic alloy layer acts as a plug,annulus seal, and base for which the resin can be placed. This not onlygives the resin something to adhere to, but the metal seal prevents theresin from running down the sides of the wellbore or from contactingreservoir fluids. The metal plug and various components such as theheater sleeve also reinforce the resin. In large diameter wellbores,flexural failure of resin plugs is a concern. However, with the metalplug and its components above in the center of the wellbore, theeffective diameter of the resin plug is reduced. The resin adheres tothe components in the center of the casing. Finally, both materials areimmiscible with the water-based fluids in the reservoirs or fluids usedduring P&A operations.

The eutectic alloy is preferably a bismuth-based alloy. Bismuth alloysare a preferred cast-in-place abandonment plug material because bismuthexpands 1-3.32% on solidification. Bismuth also has unusually lowtoxicity for a heavy metal. Furthermore, Applicant has tested thesealloys and determined that the liquid alloy does not mix with otherfluids, like cement does. Thus, the channeling common in cement plugs isavoided.

Exemplary bismuth-based alloys are described in U.S. Pat. No. 7,290,609.As a general rule, bismuth alloys of approximately 50% bismuth exhibitlittle change of volume (1%) during solidification. Alloys containingmore than this tend to expand during solidification and those containingless tend to shrink during solidification. Additional alloys aredescribed in US20150368542, which describes a bismuth alloy comprisesbismuth and germanium and/or copper. Preferably, the bismuth-based alloyis eutectic. Additional eutectic alloys to plug wells or repair existingplugs in wells are described in U.S. Pat. No. 7,152,657; US20060144591;U.S. Pat. Nos. 6,828,531; 6,664,522; 6,474,414; and US20050109511.

U.S. Ser. No. 62/402,796, filed Sep. 20, 2016, and incorporated hereinin its entirety for all purposes, also describes bismuth alloyabandonment plugs and methods of setting them. In some embodiments, thebismuth alloys are preferred due to their low melt temperatures, ease ofuse and robustness.

A low-melting point bismuth-containing alloy such as “Rose's metal”,“Kraft's alloy” or “Homberg's alloy”, or any other suitable bismuthalloy is used. Such alloys are unusual in that they have a higherdensity in liquid form than in their solid state and therefore expandupon solidification. Once deposited in a well they lose heat into thesurrounding environment, solidify, and expand to form a very secure plugwithin the well. Furthermore, there are commercially available tools andprototype tools are being developed that can heat bismuth alloy pelletsdownhole, such as the Wel-Lok, thus allowing the use of these materialsas cast-in-place abandonment plugs, but with no nonmetal components thatcould deteriorate.

The resin can be any resin typically used in P&A operations.Thermosetting resins have been used in wells (oil, gas, water or evenwaste disposal wells) before. Those having a thermal expansioncoefficient significantly greater than 10⁻³ vol % per ° C. may inprinciple be used, as long as shrinkage occurring during curing iscompensated for. Also, mixtures of resins may be used in the presentlydescribed plug.

Resin sealing materials include ThermaSet® by Wellcem AS, CannSeal® byAGR, and the WellLock® resin system by Halliburton. M&D Industries alsomakes resin plugging materials, including LIQUID BRIDGE PLUG® with arange of hardeners and accelerators. The WellLock® resin, for example,uses cross-linking between an amine hardener and epoxides, resulting ina cured three-dimensional infinite polymer network, and can be deployedwithout negative impact from exothermic reactions triggered by water.

A two-material total plug length of less than 15 meters, each portionbeing less than 5 meters, preferably less than 2 meters, will providethe same protection as the typically 30-50 meter cement plugs. Thetwo-material plug has two different sealing mechanisms, both materialsbeing immiscible with P&A work fluids (low level contamination), andboth can use gravity segregation for placement. Their complimentaryproperties and different sealing mechanisms make them as effective aslonger cement plugs.

In forming the metal seal, a tool that includes storage for the alloy aseither pellets or a layered metal, a heater, a sleeve or frame forholding and protecting the heater, and a base or canister in which thealloy is stored will be needed to place at least the first load ofalloy. The sleeve or frame protects the heater from damage as it islowered downhole and prevents direct contact with the alloy, which couldpotentially solidify therewith and prevent the heater from beingretrieved. Once the heating is finished, the heater can be removed,leaving an open sleeve with additional attachment points for the resin.

A base plug can be used for setting the metal plug, or the components ofthe heater can provide a base that is retained in the plug on removal ofthe heater portion. However, the base may be optional, as these alloystend to not travel very far before they cool and harden, thus providingtheir own base.

Multiple additions of alloy pellets may be needed to build theappropriate amount or height of alloy. Thus, the first load of alloy canbe placed by the tool, such that the alloy will be heated, and thencooled into the seal. A second, third, or more load of alloy can then beplaced using an e.g., dump bailer. The top of the open sleeve can beplugged with a “dummy” heater, or cap, while dumping the alloy. The“dummy” heater would then be pulled to allow for placement of athermite-containing heater. The thermite-containing heater is ignited toheat the additional loads of alloy to grow the height of the metal plug.

Once the metal alloy has been placed, the heater is removed (leaving thesleeve behind) and the resin is added on top of the metal seal andheater sleeve. The resin attached and adheres to the metal seal and theframe or sleeve that housed the heater. It is expected that the top ofthe tool can be removed once the initial metal seal is set, allowing forthe removal of the heater, and opening up of the heater sleeve and basefor resin attachment.

For placing the plug rock-to-rock, parts of the wellbore must be removedto allow annular access. This can be accomplished using section millingor perforation/wash operations. However, a smaller section of opening(s)is needed because the plug will be shorter than the traditional allcement or all resin plugs. However, any method of removing the stringsis acceptable, including various means of cutting the casings and othertubulars, and/or specific design of cuts or removal of the strings.

Both layers of the two-material plug are expected to expand to fill theopenings in the casing and form a rock-to rock (i.e. the seal contactsthe formation rock). However, in some embodiments, some end or terminalportions of the plug may not be rock-to-rock.

This summary is provided to introduce a selection of concepts that arefurther described below in the detailed description. This summary is notintended to identify key or essential features of the claimed subjectmatter, nor is it intended to be used as an aid in limiting the scope ofthe claimed subject matter.

As used herein, a “P&A” refers to plug and abandon. Regulations requirethat the plugs be of sufficient quality to be “permanent,” neverallowing formation fluids to leak. However, it is recognized that even apermanently plugged and abandoned well may be reopened at a later timefor various reasons. Therefore, “permanent” does not imply that the wellwill not be reopened, but instead refers to the quality of the plug—itneeding the potential to last permanently. That said, most plugsprobably won't last forever, and some degree of flexibility in meaningcan be accommodated by these terms of art.

The most effective way to prevent hydrocarbon migration in wells thathave been plugged and abandoned is to create a “rock-to-rock” seal. Thismeans the seal reaches to the formation walls.

As used herein, “casing string” and “string” are used interchangeable torefer to a long section of connected oilfield pipe that is lowered intoa wellbore and cemented. Often, multiple strings of concentric casingsare used in a wellbore.

As used herein, “dump bailer” refers to a wireline or slickline toolused to place small volumes of cement slurry, or similar material, in awellbore.

The expression “resin” refers to “classic” thermosetting resins, as wellas ductile, vulcanizable rubbers. The cured resin is expanded to atleast the volume occupied by the resin prior to curing to compensate forshrinkage.

A “Perforation” tool makes a plurality of discreet holes of roughlyequal size and even distribution, leaving the tubing otherwise intact.

The term “cast-in-place” refers to the formation of a seal in situ inthe wellbore.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims or the specification means one or more thanone, unless the context dictates otherwise.

The term “about” means the stated value plus or minus the margin oferror of measurement or plus or minus 10% if no method of measurement isindicated.

The use of the term “or” in the claims is used to mean “and/or” unlessexplicitly indicated to refer to alternatives only or if thealternatives are mutually exclusive.

The terms “comprise”, “have”, “include” and “contain” (and theirvariants) are open-ended linking verbs and allow the addition of otherelements when used in a claim.

The phrase “consisting of” is closed, and excludes all additionalelements.

The phrase “consisting essentially of” excludes additional materialelements, but allows the inclusions of non-material elements that do notsubstantially change the nature of the invention.

The following abbreviations are used herein:

ABBREVIATION TERM P&A Plug and abandonment PWC perforation/wash/clean

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Schematic of a traditional cement plug in a wellbore.

FIG. 2. Depiction of a wellbore in its initial state and after portionsthereof are removed for plug placement using section milling,perforation, or perforation/wash techniques.

FIG. 3A. A section of milled wellbore having a Wel-Lok™ tool with alloymetal.

FIG. 3B is the same well after the alloy metal has been heated andcooled to form a rock-to-rock seal.

FIGS. 4A and 4B. Removal of heater per one embodiment of the presentdescription.

FIG. 5. Place of resin on top of metal seal.

FIG. 6. Two-material plug per one embodiment of the present description.

DESCRIPTION OF EMBODIMENTS OF THE DISCLOSURE

The invention provides a novel plug for wellbore plug and abandonmentoperations. This novel plug utilizes a eutectic alloy and a resin toform a two-component plug. Because each material seals the wellboreusing different mechanisms, there is a redundancy in the seals. Thisallows for a smaller amount of materials to accomplish the same level ofsealing as traditional plugs, and a smaller amount of tubular will needto be removed. The combined two-material plug has greater integrityunder wellbore conditions than a similar total length plug of eithermaterial alone.

The present methods include any of the following embodiments in anycombination(s) of one or more thereof:

A method of plugging a well during plug and abandonment operationscomprising: a) deploying a first tool downhole to remove or perforateboth an inner tubular and/or exterior casing at a section of well to beplugged; b) deploying a second tool downhole, said second tool having aeutectic alloy in a storage space, a sleeve for holding a heater and anoptional base; c) deploying a heater downhole in said sleeve; d) heatingsaid eutectic alloy with said heater to form a molten alloy; e) allowingsaid molten alloy to expand and solidify to form a cast-in- place metalplug that fills at least part of said section of well to be plugged andseal the annulus; f) removing said heater, but not said sleeve; g)deploying a resin downhole on top of said metal plug; h) curing saidresin, wherein said cured resin adheres to and covers said cast-in-placemetal plug and said sleeve; and i) wherein said cast-in-place metal plugand said cast-in-place resin plug form a single two-material plug. Amethod of plugging a well during plug and abandonment operationscomprising: a) removing or perforating or opening both an inner tubularand an exterior casing at a section of well to be plugged; b) optionallydeploying a base plug at or near said section; c) deploying a eutecticalloy downhole on top of said base plug or at said section; d) heatingsaid eutectic alloy to form a molten alloy; e) allowing said moltenalloy to expand and solidify to form a cast-in- place metal plug thatfills at least part of said section of well to be plugged; f) removingsaid heater; g) deploying a resin downhole on top of said cast-in-placemetal plug; and, h) curing said resin to form a resin plug, wherein saidresin plug and said cast-in-place metal plug form a single two-materialplug that is a rock- to-rock plug. A method of plugging a well duringplug and abandonment operations comprising: a) deploying a first tooldownhole to remove or perforate both an inner tubular and exteriorcasing at a section of well to be plugged; b) deploying a second tooldownhole having a base, a sleeve erected therefrom for holding a heater,a heater and an alloy, wherein said alloy is stored above said base andaround said sleeve; c) heating said eutectic alloy with said heater toform a molten alloy; d) allowing said molten alloy to expand andsolidify to form a cast-in- place metal plug that fills at least part ofsaid section of well to be plugged; e) adding additional eutectic alloyto said well and repeating steps c-d until a predetermined height ofcast-in-place metal plug is formed; f) removing said heater but not saidsleeve; g) deploying or pouring a resin downhole on top of saidcast-in-place metal plug; h) curing said resin to form a resin plug,wherein said cured resin adheres to said cast-in-place metal plug,further wherein the cure resin covers said cast-in-place metal plug andsaid sleeve of said second tool; and i) wherein said cast-in-place metalplug and said resin plug form a single two-material plug that is arock-to-rock plug. Any method herein, further comprising evaluating theseal of said single two-material plug. Any method herein, wherein saidfirst tool performs section milling. Any method herein, wherein saidfirst tool performs perforation and wash operations. Any method herein,wherein said first tool opens and expands said inner tubular andexterior casing. Any method herein, wherein said eutectic alloycomprises bismuth. Any method herein, wherein said resin is athermosetting resin, a vulcanizable rubber or combinations thereof. Anymethod herein, wherein said second tool is a Wel-lok tool. Any methodherein, wherein additional alloy is added to said wellbore and thehating and solidfying steps are repeated. Any method herein, whereinsaid plug is less than 15 meters. Any method herein, wherein saidcast-in-place metal plug is less than 5 meters. Any method herein,wherein said cast-in-place metal plug is less than 2 meters. Any methodherein, wherein said rock-to-rock plug is less than 5 meters. Any methodherein, wherein said two-material plug has enhanced integrity whencompared to an equivalent total length of either material alone. Anymethod herein, wherein said method requires less time than a methodusing a two material plug comprising resin and cement. A method of P&A,wherein said method deploys a P&A plug that has two materials beingcomplementary in sealing processes, one material being an expansionmetal and one material being an adhesion resin. Any method herein,wherein deploying said P&A plug that requires less time than twomaterial plug comprising resin and cement. Any method herein, whereinsaid two material plug has enhanced integrity when compared to eithermaterial alone. A plug for a wellbore comprising: a) an eutectic alloybase layer, and b) a resin layer above and in physical contact with saideutectic alloy base layer. Any plug herein, wherein said eutectic alloybase layer and/or said resin form a “cast-in-place” seal. Any plugherein, wherein said eutectic alloy base layer is bismuth and/or saidresin is a thermosetting resin, a vulcanizable rubber or combinationsthereof. Any plug herein, further comprising a sleeve for a heaterembedded in the resin and eutectic alloy base alloy layer.

The present invention is exemplified with respect to the descriptionbelow and FIG. 2-6. However, this is exemplary only, and the inventioncan be broadly applied to any wellbore that is being abandoned. Thefollowing examples are intended to be illustrative only, and not undulylimit the scope of the appended claims.

The first step in plugging a wellbore is to create access to the annulusby cutting through the strings. FIG. 2 displays wellbores that has beenmodified by the most commonly used methods to contrasts these methodswith a wellbore in its initial state (200). The most commonly usedoptions to access the annulus are section milling (201), wherein anentire section of the casing string is removed; slot perforation (202),wherein slots are cut into the casing string over; and perforation/wash(203), wherein slots are cut into the casing string and a circulatedfluid cleans the annular space to remove debris from the perforations.

Annular access allows for placement of rock-to-rock seals using thealloy and/or resin. While each of the commonly used techniques to gainaccess has its own advantages or disadvantages, any method of openingaccess to the annulus can be used with the described plug. For instance,Ser. No. 62/470,234, filed Mar. 11, 2017, describes a technique thatcuts helical coils into the strings to create openings in the casingthat will aid in the formation of multiple o-ring type mini-seals as thematerial expands into the opening.

Once the strings are cut or milled, operations to set the plug materialcan proceed. The section of the wellbore that is milled or perforated iscalled a “window.” The eutectic alloy, preferably a bismuth-based alloy,is placed at the bottom of the window and heated. The alloy is inert,environmentally friendly and is not affected by corrosion, hydrogensulfide or acidic attack. A base plug may be needed to support themolten alloy in some embodiments, but in other embodiments, a tool isused that provides its own base, or the base is omitted and the moltenalloy forms its own base.

Though this plug is being described as being set in a wellbore with anintentionally opened annulus, the bismuth-based alloy can also be set inundamaged, damaged or corroded casing due to the molten alloy flowinginto any profile or shape.

The metal alloy plug must be placed first because its acts as a base ofsupport, seals the annuli, and an attachment point for the resin. Anywellbore tool, such as a dump bailer, with the ability to place pelletsor sheets of the alloy can be used. Depending on the chosen tool, a baseplate may have to be installed at or below the bottom of the window toprevent the molten alloy and/or alloy pellets from draining down thewellbore. The base plug need not be perfect, and may be omittable,because the alloy will flow a fairly limited distance before solidifyingsealing the well bore and annulus. Any known base plate and methods ofinstallation can be used.

Preferably, the alloy is placed using a Wel-Lok™ tool from BiSN OilTools. The Wel-Lok™ tool is preferred over other tools because it has astorage space for alloy layers (302) and a heater (301) in a sleeve, asshown in FIG. 3A. Further, the bottom of the Wel-Lok™ tool can act as acooling shelf (303) for the molten alloy to solidify (304) upon after itflows out of the storage space, as shown in FIG. 3B.

The Wel-Lok™ tools have a bismuth-based alloy that is melted in situusing a chemical reaction heater. The molten alloy is then able to flowfrom its storage space on the tool and expand into the annulus spacetowards the formation. As mentioned above, the bottom of the Wel-Lok™tool has a shelf which will be several degrees cooler than the moltenalloy and can act as a cool area to slow the flow of the heated alloy sothat it is not lost down the well, but instead cools in the targetregion.

If more bismuth-based alloy is needed to adjust the height of the metalseal, it can be added using a dump bailer or other tool. The sleeve canbe temporarily plugged with a “dummy” heater or some other blockingdevice during the addition of new alloy, then removed as needed forplacement of the actual heater (301) in the sleeve. As before, a heater(301) is placed in the sleeve to heat the new alloy. As the metal sealis created, the frame or sleeve encompassing the heater will become partof the seal and provide an additional surface for the resin to adhere.The frame or sleeve is generally a hollow open-ended shape, usuallytubular to maximize the space usage in a tubular well. However, othershapes are possible, such as sleeves having a square or triangular crosssection.

The top (401) of the Wel-Lok™ (400) or similar tool should be removableto pull the heater (402) out of its sleeve (403), per FIGS. 4A and 4B.The top (401) can be removed by shearing it off or melting pins thatwere used to keep the top and heater in place. For instance, the top canbe removed using a cutter. Removing the heater would open the sleeve orframe and allow for the resin (501) to be placed in the open frame, perFIG. 5. The added surface area of the open sleeve or frame leads to moreattachment points for the resin to adhere. Enough resin, however, isneeded to fully cover the sleeve or frame to prevent any imperfectionsor open pockets in the resin seal.

In evaluating the plug, the metal alloy portion can be pressure testedwithin hours, which provides significant costs savings when compared tocement or resin, which can require one or more days to set. Because truemetal-to-metal and metal-to-wall seals are made, a permanent gas/liquidtight seal is created for any oil well abandonment.

If the metal alloy portion of the plug is found to have created auseable seal, then the resin can be added to the top of the metal sealand frame using a dump bailer (502), poured from the surface and fallthrough the P&A fluid to the metal alloy plug, (503) or placed withpipe, tubing, or coil tubing (504). The resin will flow through theframe from the heater and flow out towards the formation. As the resinis immiscible and typically has a specific gravity higher than fluid inthe well bore it will fall and displace the fluid on top of the metalplug.

Access to the annulus can be obtained by methods outlined previously,section milling, perforation, PWC, or expansion and opening, andcombinations thereof. The plug placement process is basically the samefor these methods. There may be variations in volume of metal alloy andresin. For example, PWC might require a longer metal plug to insure theannulus is sealed because alloy must flow through perforations to sealthe annulus. If a well is just perforated, then a longer resin plug maybe placed and squeezed into the perforations.

Enough resin is needed to plug the remaining open space in the casingstrings and cover the top of the heater sleeve while compensating forshrinkage that occurs as the resin cures, as the final resin plug (600)is exemplified in FIG. 6.

Shrinkage is a potential issue that has to be addressed in resin-onlyplugs, but is less of an issue with the cast-in-place eutectic alloybase plug thereunder. The resin can be squeezed slightly against themetal base plug to insure adhesion to the well bore surfaces. Thissqueezing will compensate for shrinkage as it will enhance adhesionensuring gas tightness of the well. With the metal bottom layer thatforms a rock-to-rock seal, shrinking of resin in the present inventiondoes not lead to plug failure as adhesion can be enhanced.

The traditional tests to confirm plug integrity can be used inevaluating the installed plug positive pressure tests and negativepressure tests, inflow tests, and the like. If logging is desired theplug could be drilled out and logged. The resin could contain a tracerof some sort for logging. However, generally cement P&A plugs are notdrilled out, and are logged with pressure and tagging tests being themost common method of testing plugs.

Once in place and sufficiently sealing the wellbore, the remainingabandonment operations can proceed as normal.

The following references are incorporated by reference in theirentirety.

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US20150053405 One trip perforating and washing tool for plugging andabandoning wells

COP 42455, U.S. Ser. No. 62/402,821, Sep. 30, 2016.

COP 42425, U.S. Ser. No. 62/402,810, Sep. 30, 2016.

COP 42423, U.S. Ser. No. 62/402,802, Sep. 30, 2016.

COP 42472, U.S. Ser. No. 62/470,234, filed Mar. 11, 2017

The invention claimed is:
 1. A method of plug and abandonment (P&A) of awell, wherein said method comprises deploying a cast-in-place P&A pluginto a well to be plugged and thereby plugging said well, said P&A plugcomprising two materials, a first material being an expansion metalbelow a second material being an adhesion resin, wherein said P&A plughas greater integrity, under wellbore conditions, than a rock-to-rockplug of equal length with either said first material alone or saidsecond material alone.
 2. The method of claim 1, wherein deploying saidP&A plug requires less time than deploying a two-material plugcomprising resin and cement.
 3. The method of claim 1, wherein saidexpansion metal is a base of the P&A plug and said adhesion resin isabove the expansion metal and in physical contact therewith.
 4. A methodof plug and abandonment (P&A) of a wellbore comprising: a. removing partof a wellbore casing at a location to be plugged to form a window toallow annular access; b. deploying a P&A plug that has two materials atsaid location to be plugged, wherein said deploying comprises: i.placing a first material being an expansion metal in the wellbore atbottom of the window; ii. heating and cooling said expansion metal,thereby expanding said expansion metal to form a cast-in-placerock-to-rock metal seal in the wellbore; iii. adding a second materialbeing an adhesion resin onto said metal seal; and iv. curing theadhesion resin to form a rock-to-rock seal; wherein said P&A plug hasgreater integrity, under wellbore conditions, than a rock-to-rock plugof equal length with either said first material alone or said secondmaterial alone.
 5. The method of claim 4, wherein deploying said P&Aplug requires less time than deploying a two-material plug comprisingresin and cement.
 6. The method of claim 4, further comprisingevaluating a sealability of the P&A plug.
 7. The method of claim 4,wherein said expansion metal comprises bismuth.
 8. The method of claim4, wherein said adhesion resin is a thermosetting resin, a vulcanizablerubber or combinations thereof.
 9. A method of plug and abandonment(P&A) of a wellbore comprising: a. removing or perforating a part of awellbore inner tubular, casing or both the inner tubular and casing at alocation to be plugged to form a window to allow annular access; b.deploying a P&A plug that has two materials at said location to beplugged, wherein said deploying comprises: i. placing a first materialbeing an expansion metal at the window; ii. heating and cooling saidexpansion metal, thereby expanding said expansion metal to form arock-to-rock metal seal; iii. adding a second material being an adhesionresin onto said metal seal; and iv. curing the adhesion resin to form arock-to-rock seal; wherein said P&A plug has greater integrity, underwellbore conditions, than a rock-to-rock plug of equal length witheither said first material alone or said second material alone.
 10. Themethod of claim 9, wherein deploying said P&A plug requires less timethan deploying a two-material plug comprising resin and cement.
 11. Themethod of claim 9, further comprising evaluating a sealability of theP&A plug.
 12. The method of claim 9, wherein said expansion metalcomprises bismuth.
 13. The method of claim 9, wherein said adhesionresin is a thermosetting resin, a vulcanizable rubber or combinationsthereof.